Publication Details

Category Text Publication
Reference Category Journals
DOI 10.1016/j.soilbio.2024.109403
Licence creative commons licence
Title (Primary) Assessing energy fluxes and carbon use in soil as controlled by microbial activity - A thermodynamic perspective A perspective paper
Author Kästner, M.; Maskow, T. ORCID logo ; Miltner, A. ORCID logo ; Lorenz, M.; Thiele-Bruhn, S.
Source Titel Soil Biology & Biochemistry
Year 2024
Department MIBITECH; MEB
Volume 193
Page From art. 109403
Language englisch
Topic T7 Bioeconomy
Keywords Calorimetry; Microbial growth; Gibbs energy; Enthalpy; Soil organic matter; CUE; EUE
Abstract Soil organic matter (SOM) plays a central role for both the C cycle and soil functions. Plants provide the input and heterotrophic (micro)organisms are essential for the turnover. Microbial metabolism links matter and energy fluxes and generates the highest energy turnover dynamics in SOM because the organisms need both energy and matter for maintenance and growth. In this perspectives paper, we evaluate the knowledge on thermodynamic approaches potentially applicable to study the turnover of organic matter in the soil system. Thermodynamics is essential for understanding organic matter turnover in soil as turnover and storage are controlled by the energy supply to, and consumption by, microbes. Instead of just comparing the heat of combustion of compounds without considering microbial anabolism, we need to apply conventional thermodynamic state variables that can be either estimated using established thermodynamic equations, or measured empirically in soil. In particular, we can follow and quantify overall changes of enthalpies by calorimetry. Here, we suggest to apply a thermodynamic concept with the related experimental approaches of calo(respiro)metry and turnover mass balances including biomass formation. This enables us to better interpret and understand the highly variable carbon use efficiency (CUE) in a multi-substrate system such as soil and to relate this to energy use efficiency (EUE). Combining the experimental measurements of the thermodynamic state variables with mass turnover data allow prediction of whether compounds can be metabolized with energy delivery to microorganisms, or be thermodynamically stabilized under the respective redox and electron acceptor conditions. Energy balancing shows how much energy is actually used and retained in the soil, how much is emitted as heat, and how much may be stabilized due to endergonic turnover reactions. Thermodynamic stabilization should therefore be considered as basic stabilization process for organic compounds in soil.
Persistent UFZ Identifier
Kästner, M., Maskow, T., Miltner, A., Lorenz, M., Thiele-Bruhn, S. (2024):
Assessing energy fluxes and carbon use in soil as controlled by microbial activity - A thermodynamic perspective A perspective paper
Soil Biol. Biochem. 193 , art. 109403 10.1016/j.soilbio.2024.109403